Computational design of iris folding patterns

Computational Visual Media - Iris folding is an art-form consisting of layered strips of paper, forming a spiral pattern behind an aperture, which can be used to make cards and gift tags. This...     

3D interactive topology optimization on hand-held devices

This educational paper describes the implementation aspects, user interface design considerations and workflow potential of the recently published TopOpt 3D App. The app solves the standard minimum compliance problem in 3D and allows the user to change design settings interactively at any point in time during the optimization. Apart from its educational nature, the app may point towards future ways of performing industrial design. Instead of the usual geometrize, then model and optimize approach, the geometry now automatically adapts to the varying boundary and loading conditions. The app is freely available for iOS at Apple’s App Store and at http://www.topopt.dtu.dk/TopOpt3D for Windows and OSX.     

An Example-based Procedural System for Element Arrangement

We present a method for synthesizing two dimensional (2D) element arrangements from an example. The main idea is to combine texture synthesis techniques based‐on a local neighborhood comparison and procedural modeling systems based‐on local growth. Given a user‐specified reference pattern, our system analyzes neigh‐borhood information of each element by constructing connectivity. Our synthesis process starts with a single seed and progressively places elements one by one by searching a reference element which has local features that are the most similar to the target place of the synthesized pattern. To support creative design activities, we introduce three types of interaction for controlling global features of the resulting pattern, namely a spray tool, a flow field tool, and a boundary tool. We also introduce a global optimization process that helps to avoid local error concentrations. We illustrate the feasibility of our method by creating several types of 2D patterns.     

Asset Pricing and Productivity Growth: The Role of Consumption Scenarios

The paper analyzes the performance of asset prices implied by an aggregate macroeconomic growth model under two different consumption hypotheses: overlapping generations of agents with two period lives versus the infinitely lived agent. The production side of the economy is described by a random growth model with a competitive labor market and an exogenously given random dividend payout ratio. For an isoelastic technology with multiplicative production shocks this implies a random dynamical system for the firm’s rate of profit with a unique asymptotically stable random fixed point for a large class of productivity growth and dividend payout ratio processes. Based on an extensive numerical study of stationary solutions we show that the two consumption scenarios imply a limited number of diverse effects regarding equity and bond returns and equity premia.     

Enzyme-linked immunosorvent assay using vertical microreactor stack with microbeads

The advantages of vertical microreactor stack with three-dimensional (3D) structure for immunoassay are discussed. The vertical microreactor stack uses vertical fluid flow operation with multifunctional fluid filters. The multi function of fluid filter is very effective for micromixing and passive valve operation. The mechanism of micromixing is discussed by using computational fluid dynamics (CFD), and we know that the mixing mechanism based on Coanda effect. To evaluate the micromixing performance of fluid filter, we demonstrated enzyme reaction with unique repeat mixing operation. As the results, we proved that the fluid filter has very effective mixing performance. The detection limit, which demonstrated by competition enzyme-linked immunosorvent assay (ELISA), is comparable with recommended detection limit, which suggested by Japanese ministry for the environment.     

High efficiency mixing by the use of cross-linked micro capillary fluid filter

A novel type passive mixing device that causes the three-dimensional flow was proposed. This mixer consists of the integrated capillary bundle structure. And the capillaries ware cross-linked each other. So it is called cross-linked micro capillary filter. The mixing effect of the cross-linked micro capillary filter was calculated by the computational fluid dynamics (CFD). The fluid behaviour in the fine three-dimensional structure could be analysed by the use of CFD. In the result of CFD calculation, the cross-linked micro capillary filter estimated high mixing effect. Moreover, the mixing efficiency was become higher by change the cross-linked form. The calculation result was decided the form of the cross-linked micro capillary filter. And this filter was fabricated by application of the Deep X-ray lithography. To form the cross-linked capillary, it was operated twice exposures. In these exposures, respectively the exposure stage was tilted to difference angle. The cross-linked capillary filter fabricated in this way was applied to vertical fluid flow operation. This cross-linked capillary filter could hold and transmit the fluid by the switchover of in impressed pressure. Herewith the cross-linked micro capillary filter showed availability as high efficiency mixing device.     

High‐pixel‐rate grating‐light‐valve laser projector

Abstract— A high‐pixel‐rate, high‐contrast (30,000:1) wide‐color‐gamut grating‐light‐valve laser projector is reported. A new optical engine enabling high‐frame‐rate (240 Hz) scan projection is employed. Panoramic wide‐angle‐scan projection with a 64:9 aspect ratio was also developed. Speckle noise is eliminated using a simple but highly efficient technique. The optical throughput efficiency of the grating‐light‐valve laser projector is reviewed.     

Observation of three-dimensional elemental distributions of a Si device using a 360 degrees -tilt FIB and the cold field-emission STEM system

A technique for preparation of a pillar-shaped specimen and its multidirectional observation using a combination of a scanning transmission electron microscope (STEM) and a focused ion beam (FIB) instrument has been developed. The system employs an FIB/STEM compatible holder with a specially designed tilt mechanism, which allows the specimen to be tilted through 360 degrees [T. Yaguchi, M. Konno, T. Kamino, T. Hashimoto, T. Ohnishi, K. Umemura, K. Asayama, Microsc. Microanal. 9 (Suppl. 2) (2003) 118; T. Yaguchi, M. Konno, T. Kamino, T. Hashimoto, T. Ohnishi, M. Watanabe, Microsc. Microanal. 10 (Suppl. 2) (2004) 1030]. This technique was applied to obtain the three-dimensional (3D) elemental distributions around a contact plug of a Si device used in a 90-nm technology. A specimen containing only one contact plug was prepared in the shape of a pillar with a diameter of 200nm and a length of 5mum. Elemental maps were obtained from the pillar specimen using a 200-kV cold-field emission gun (FEG) STEM model HD-2300C equipped with the EDAX genesis X-ray energy-dispersive spectrometry (XEDS) system through a spectrum imaging technique. In this study, elemental distributions of minor elements with weak signals were enhanced by applying principal component analysis (PCA), which is a superior technique to extract weak signals from a large dataset. The distributions of elements, especially the metallization component Ti and minor dopant As in this particular device, were successfully extracted by PCA. Finally, the 3D elemental distributions around the contact plug could be visualized by reconstruction from the tilt series of maps.     

Slot-electrode optical modulator using KTiOPO(4)

A slot-electrode optical modulator is introduced and demonstrated with KTP at 532 nm. A switching voltage of 45 V, risetime of 3.5 ns, and power capability of more than 7 Ware measured. DC modulation without application of DC voltage is discussed. Further optimization can reduce the switching voltage to 18 V.     

-Structure of the respiratory system of the Ulodera Hynobius neblosus tokyoensis Tago, with special reference to the distribution of serotonin-immunoreactive cells in its respiratory tract epithelium

The respiratory tract epithelium in many vertebrate species has a neuroepithelial endocrine (NEE) system. This system is composed of solitary NEE cells or organoid cell groups called neuroepithelial bodies (NEBs). In response to chemical and physical stimuli, NEE cells may release bioactive substances. Serotonin, one of the biogenic amines, well-known as a constricter of smooth muscle, can be found in NEE cells, serotonin-immunoreactive cells can be used as a marker for these cells. Comparative histological studies of lower vertebrates can improve our understanding of mammalian respiratory systems. The Tokyo salamander (Hynobius neblosus tokyoensis Tago), classified as Ulodera, is particularly useful for comparative studies of respiration. In this study, the serial sections of respiratory tract of the Tokyo salamander were stained by a commonly used staining method and by an immunocytochemical method for serotonin, and the distribution of serotonin-immunoreactive cells in the respiratory tract was examined. The respiratory tract was found to be connected to the alimentary tract via an aditus laryngis, which opens on the medio-ventral side of the esophagus. The laryngotrachea was slit-like or elliptically shaped with a total length of about 3.5 mm, joining the aditus laryngis. The laryngotrachea was supported by a pair of lateral cartilages, and a fibromuscular layer was seen between the cartilages and the epithelium. In the cranial region, a laryngeal sphincter was seen around the laryngotrachea. The laryngotrachea branches into a pair of tube-like lungs, that are about 17-20 mm in length. Two apposed primary trabeclae run along the entire length of the lung wall, perpendicular to the axis, and containing the pulmonary arteries and veins. The lungs were divided into two portions: 1) an airway portion (trabeclae, septa) in which smooth muscles surrounding the large vessels were well developed, and 2) a respiratory portion which was give that name because it has well developed capillary networks that were assumed to be involved in gas exchange. The lumen of the laryngotrachea and the pulmonary airway portion contained pseudostratified cilio-mucous epithelium. In the caudaldorsal region of the laryngotrachea adjacent to the lungs, the non-ciliated respiratory epithelium was seen lining the capillaries. In cilio-mucous epithelium of the laryngotrachea, all serotonin-immunoreactive cells were solitary. They apposed to be columnar, cuboidal, triangular, oval, and flask- or spindle-shaped. Solitary serotonin-immunoreactive cells were classified "open type cell" with appical process reaching to the luminal surface and "closed type cell" insulated from the lumen by an epithelial lining. In the pulmonary airway portion, serotonin-immunoreactive cells were solitary cells and in clusters. Serotonin-immunoreactive cells were widely distributed throughout the respiratory tract, but they tended to be found mainly in the cranial portion. The density was highest in the area with the laryngeal sphincter, and decreased caudally in the laryngotrachea and lung. No serotonin-immunoreactive cells were found in the respiratory portion of the dorsal-caudal area of the laryngotrachea or in the part of the lung with non-ciliated cells. So the structure and distribution of serotonin-immunoreactive cells in the respiratory tract of the Tokyo salamander are similar to those of NEE cells and NEBs in mammalian respiratory systems. The density of serotonin-immunoreactive cells appears to be related to the distribution of smooth muscles in the fibromuscular layer and airway portion. The cells may be involved in regulation of the respiratory system. Serotonin is released in response to stimulation, which could result in constriction of the fibromuscular layer and shrinkage of the laryngotracheal cavity, and may regulate pulmonary volume by constricting smooth muscles